We did last April in Grand Cayman. The extreme dolphin swim w/push and pull was awesome. Be prepared to pay for pics at the end as no cameras were allowed but the experiance was a once in a lifetime. We each got to be pushed by the dolphins by our feet across the pool and then got to hold on to their fin while they swan around. Truly unforgettable.
If you do this try to get a morning time. We did the afternoon one and were the second tender to the last back to the ship. Was hoping for some time to explore but underestimated the time the excursion would take. Took up about 3-4 hours toatl including travel time.